Spark plug Bosch or OEM Mazda

My 2017 VW Jetta 1.4 5M - at 67760 miles on the factory original plugs - now has new Bosch Iridium/Plattinum plugs - (YA5KIP80)..................(the only symptom on the old plugs was a MPG drop - no hard starting, no missing, no rough idle......... EZ

changed out the spark plugs, all except for cyl 1 had crazy looking plugs. Used Bosch platinum 6704 cleared up the CEL and also the stability and TC lights no longer flash so somehow that was connected I guess.

For iridium spark plug. Do NOT gap them. I have bosch double iridium spark plugs and over 120K miles now. Still goes strong.

My car has Bosch Double Iridium spark plugs. Over 120K miles now still go strong.

I just got Bosch ones for my 2gr in the Lexus. Worked well, no complaints. And they weren’t badly priced

I learned this after installing Bosch plugs in a Honda many moons ago. Japanese cars like Japanese-designed plugs.

Ja tive problema com velas bosch. NGK é melhor.

I personally refuse to put anything Bosch made in my cars. All were genuine Bosch parts from my local parts place that has never done me wrong.

First it was their wipers, paid good money for them, squeeled worse than the worn old ones. Figured it's a fluke.

Then I had a set of spark plugs, they were gapped correctly, but the car ran like absolute garbage and I couldn't figure it out until I put the probably 20 year old Valeos back in and it ran fine again.

Then I had a crankshaft sensor that was bad out of the box, and that was the last straw for me. I don't care if it's coincidence or a bad batch, or if they've improved it since, I'm done with any Bosch parts unless it's NOS from the early 2000s or earlier.

My 2000 with California emissions (regular cat and then two pre-Cats at the exhaust headers) would only run properly with the oem spec NGKs. Threw Bosch in their once and it ran terribly.

Ever since Bosch moved spark plug production to Russia, the quality has been sketchy.